Retractable spray shield for agricultural use

ABSTRACT

A retractable spray shield for agricultural use has a spray barrier; a clam-shell storage tube; a deployment and concealment drive having a motor, a drive shaft, and a quadrilateral linkage that in one direction deploys the spray barrier from the storage tube and in a second opposed direction conceals the spray barrier within the clam-shell storage tube. The quadrilateral linkage is defined by a rotating arm; a pushing arm coupled to the drive shaft; the bottom of the claim-shell storage tube, and a hinge plate supporting the spray barrier. The spray barrier has a generally triangular and flaccid liquid barrier film, a pair of framing legs coupled to opposed edges of the liquid barrier film, and a spring configured to operatively stretch the pair of framing legs apart from each other and thereby expand the barrier film toward a planar, generally triangular geometry when deployed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation-In-Part of U.S. patentapplication Ser. No. 15/968,728 filed May 1, 2018, which in turn is aContinuation-In-Part of U.S. patent application Ser. No. 15/407,229filed Jan. 16, 2017 and granted as U.S. Pat. No. 10,315,211 on Jun. 11,2019, Ser. No. 15/968,728 that also claims the benefit of U.S.provisional patent application 62/492,567 filed May 1, 2017, each oflike title and inventorship, the teachings and entire contents of eachwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention pertains generally to fluid spraying, and moreparticularly to a retractable spray shield for agricultural use thatdeflects the flow from at least one spray nozzle.

2. Description of the Related Art

Modern agriculture has for most of a century advanced in productivitymore than many other industries. Most consumers are generally unaware ofthese significant advances. However, the consumer has benefittedgreatly, in particular because of the lower-than-inflation price changesin many agricultural products through this long time period. Mostagricultural operations today incorporate extremely technically advancedmachinery, seed, and chemicals that allow one person to do the work thateven only a few decades ago required many. One particularly common andexemplary machine is the tractor, which has increased greatly in size,power, and in the many diverse attachments that are used to facilitateoperations.

The commercial production of many agricultural crops involves thespraying of one or more chemicals such as herbicides, fertilizers,insecticides, or fungicides. The products being sprayed may be used toimprove the health of the desired crop, or to eliminate or reducedetrimental interaction with diseases, pests, and competing weeds. Toreduce the time required to apply these products to the crop, very largesprayers have been produced that carry a large liquid tank, a pumphaving a fluid inlet coupled into the liquid tank, at least one boom armtypically extending generally transversely to the direction of travel,and a plurality of spray nozzles supported by the boom and coupledthrough liquid supply lines to the pump outlet. The sprayer may be anattachment to a tractor, or an entirely separate machine. A personoperating the sprayer will typically be able to control the pump to turnon or off the spray, and in many cases to control the pump pressure,which in turn controls the rate of delivery of the liquid to the crop.Through the use of this equipment, spraying of liquid chemicals is bothtime efficient and controllable to the needs of a particular crop,field, or even location within a field. As a result, a relativelyprecise amount of chemical may be applied rapidly to a large area.

As may be appreciated, the quantity of spray delivered to a crop can berelatively precisely controlled beneath the boom. When multiple passesare made across a field, for each pass the end of the boom arm can belocated offset by the right amount from the previous pass to providejust the right amount of overlap in the spray coming out beyond the endof the boom. However, the sprayer will only pass over the edges of thefield once. Consequently, adjacent to the edges of the field a tractoroperator will normally make sure the last row of crop will be under thelast sprayers, to ensure adequate liquid is delivered to this final row.Unfortunately, this also means that spray will be delivered beyond thelast row of crop, typically on to adjacent plants. As may beappreciated, these adjacent plants are not a part of the desired crop,and so may include an adjacent field containing a different crop, agrass covered ditch, a neighboring property under different ownership,or undesirable weeds.

In the case of the application of an herbicide with the oversprayfalling onto a different crop, a grass covered ditch, or a neighboringproperty, those adjacent plants undesirably may be killed or seriouslyharmed by the spray. In the case of undesirable weeds, and since theseweeds are not immediately under the boom and are instead being treatedwith overspray, the concentration of application is generally less thanthat intended for application to the field. As a result, the overspraymay not be sufficient to kill the weeds, and so may instead lead to thedevelopment of weeds resistant to the spray. These weeds may thenencroach upon the desired crop, hurting the yield or value of theharvested crop. Similar deficiencies may be encountered in the case ofinsecticides and fungicides, such as where adjacent insects may developinsecticide resistance. In the case of a fertilizer overspray, adjacentweeds may be undesirably strengthened and stimulated. Consequently, andfor a variety of reasons, it is desirable to reduce or eliminateoverspray adjacent to the edges of a field, while not interfering withthe spray within the middle of the field.

To reduce the overspray, artisans have designed various shields that aredesigned to enclose a single row of crop. The spray nozzles are mountedto spray into the interior of the shield, and thereby avoid spray intothe between row spaces and to prevent overspray. Exemplary U.S. patentsand published applications, the teachings which are incorporated hereinby reference, include: U.S. Pat. No. 3,445,961 by Elsworth, entitled“Agriculture spraying machines”, which illustrates a pair of plasticguides that gently squeeze the plants together, and a liquid that issprayed interior of the guides into the squeezed plants; and U.S. Pat.No. 4,947,581 by Claussen et al, entitled “Spray shield assembly”, whichillustrates a set of shields in the general shape of an upside-down “U”channel open on both ends but closed on the top and sides. For someapplications, such as that of a fertilizer, either of these apparatuswill reduce or avoid undesirable overspray on to other plants besidesthe agricultural crop. However, for other liquid applications,particularly herbicide applications, the entire field needs to besprayed, making these shields useless for such applications.Furthermore, these shields must be set for a particular row spacing,meaning they will typically require resetting for each different speciesof crop. The variable height of different species and different stagesof maturity are also challenging. Finally, there are many times when aspray will be most effectively sprayed by nozzles spraying at an anglecloser to parallel to the ground than perpendicular thereto. Spray fromrelatively more horizontally pointing nozzles that misses theimmediately adjacent row of crop, such as when the spray nozzle ispointing between sequential plants in a row, may still end up beingapplied to plants in a nearby row. In the case of a shield such asillustrated by either Elsworth or Claussen et al, any spray that missesthe plant will instead be applied only to the shield, and from therewill drip onto the soil without ever contacting the plant.

Additional U.S. patents illustrate fixed shields for crops, the relevantteachings and contents which are incorporated herein by reference,including: U.S. Pat. No. 2,589,020 by North, Jr, entitled “Sprayingdevice”; U.S. Pat. No. 4,274,589 by Jones, entitled “Spraying apparatusemploying a skirt structure”; U.S. Pat. No. 4,986,473 by Semple et al,entitled “Crop sprayer shield”; U.S. Pat. No. 5,139,200 by Greimann etal, entitled “Shield for agricultural sprayer”; U.S. Pat. No. 7,063,273by Hahn et al, entitled “Spray delivery system”; and U.S. Pat. No.8,573,510 by Bisson et al, entitled “Drift shroud system for spray boomsof turf sprayer”. Unfortunately, these prior art shields are quite largeand designed to operate close to the ground, and so are susceptible todamaging interference with rocks, roots, mounds, and other obstacles inthe ground. As with the Elsworth or Claussen et al shields, theseshields are fixed in geometry. This means that even in the middle of thefield, the farthest transverse edges (the left and right extremes) ofthe shields will undesirably block spray from reaching plants, and willinstead drip the spray onto the earth. Any fixed shields that do notblock the spray on the transverse edges will likewise not prevent theundesirable overspray discussed herein above.

Additional patents of varying relevance, the relevant teachings andcontents which are incorporated herein by reference, include: U.S. Pat.No. 3,565,341 by Burroughs, entitled “Spraying apparatus”; U.S. Pat. No.4,124,221 by Goings, entitled “Spray guard for vehicles”; U.S. Pat. No.4,927,080 by Alsing, entitled “Field spraying device”; U.S. Pat. No.5,062,572 by Reiter et al, entitled “Spray shield”; U.S. Pat. No.5,549,457 by Flores et al, entitled “Pavement sprayer having movablespray guard”; U.S. Pat. No. 8,066,304 by Ulgen, entitled “Retractablemud flap for vehicles”; and Des U.S. Pat. No. 702,124 by Harrower et al,entitled “Rotatable spray shield device”.

In addition to the foregoing patents, Webster's New Universal UnabridgedDictionary, Second Edition copyright 1983, is incorporated herein byreference in entirety for the definitions of words and terms usedherein.

As may be apparent, in spite of the enormous advancements in agricultureand substantial research and development that has been conducted, therestill remains a need for a spray shield that will permit efficientspraying in the middle of a field while also selectively blockingoverspray at the field edges.

SUMMARY OF THE INVENTION

In a first manifestation, the invention is a selectively deployablespray shield for agricultural use. A spray barrier has a generallytriangular and flaccid liquid barrier film, a pair of framing legs, eachof the pair of framing legs coupled to an opposed edge of the liquidbarrier film, a hinge plate, a first pintle coupling a first one of thepair of framing legs to the hinge plate, a second pintle coupling asecond one of the pair of framing legs to the hinge plate, a springguide post intermediate between the first and second pintles, and atension spring wrapped about the spring guide post configured tooperatively stretch the pair of framing legs apart from each other andthereby expand the spray shield toward a planar, generally triangulargeometry. A clam-shell storage tube defines a path for the hinge plateto reciprocate along, and is configured to receive and conceal the sprayshield on an interior when the clam-shell storage tube is closed. Adeployment and concealment drive has a motor, a drive shaft, and aquadrilateral linkage including a rotating arm and a pushing arm coupledwith the drive shaft. The drive shaft rotates the pushing arm relativeto the clam-shell storage tube and thereby also rotates the rotating armrelative to the clam-shell storage tube between a first concealedposition having the rotating and pushing arms parallel and adjacent tothe clam-shell storage tube and the spray barrier concealed within saidclam-shell storage tube to a second deployed position having the pushingarm parallel and adjacent to the clam-shell storage tube and the spraybarrier deployed outside the clam-shell storage tube.

In a second manifestation, the invention is, in combination, anagricultural spray machine, an agricultural spray boom, and aretractable spray shield for agricultural use. The agricultural spraymachine has an operator cab; an electrical system; a drive train; aliquid tank; and a pump receiving a liquid held within the liquid tank.The agricultural spray boom has a boom arm extending transverse to aforward direction of travel of the agricultural spray machine; and atleast one spray nozzle suspended from the boom arm and in fluidcommunication with the pump. The retractable spray shield foragricultural use has a hinge plate; a liquid barrier film extending fromthe hinge plate; a clam-shell storage tube defining a path for the hingeplate to reciprocate along, and adapted to receive and conceal the sprayshield on an interior when the clam-shell storage tube is closed; adeployment and concealment drive having a motor, a drive shaft, and aquadrilateral linkage including a rotating arm and a pushing arm coupledwith the drive shaft, the drive shaft rotating the pushing arm relativeto the clam-shell storage tube and thereby also rotating the rotatingarm relative to the clam-shell storage tube between a first concealedposition having the rotating and pushing arms parallel and adjacent tothe clam-shell storage tube to a second deployed position having thepushing arm parallel and adjacent to the clam-shell storage tube; and aboom arm coupler adapted to couple the retractable spray shield to theagricultural spray boom and simultaneously locate the liquid barrierfilm in the second deployed position adjacent to and in a spray patternof the at least one spray nozzle.

Objects of the Invention

Exemplary embodiments of the present invention solve inadequacies of theprior art by providing a retractable spray shield for agricultural use.The retractable spray shield has a liquid barrier film; a storage tube;a deployment and concealment drive that in one direction deploys theliquid barrier film from the storage tube and in a second directionopposed to the first direction conceals the liquid barrier film withinthe storage tube; and a pivotal quick release support and boom armcoupling.

The present invention and the preferred and alternative embodiments havebeen developed with a number of objectives in mind. While not all ofthese objectives are found in every embodiment, these objectivesnevertheless provide a sense of the general intent and the many possiblebenefits that are available from embodiments of the present invention.

A first object of the invention is to provide an apparatus that may bedeployed to reduce or eliminate overspray adjacent to the edges of afield, and which may be concealed so as to not interfere with spraywithin the middle of the field. A second object of the invention is toenable the apparatus to be deployed or concealed from within the cab ofa spray vehicle, without necessitating the operator to disembark fromthe cab. Another object of the present invention is to facilitate thespraying of a variety of fields, without the need for mechanicaladjustment to a particular species, or plant height and maturity. Afurther object of the invention is to provide apparatus that iseffective with a spray emanating generally at an angle closer toparallel to the ground than perpendicular thereto. Yet another object ofthe present invention is to achieve the foregoing objectives with anapparatus that is easily fabricated and which may be easily installedupon both new and existing spray boom arms.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, advantages, and novel features of thepresent invention can be understood and appreciated by reference to thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 illustrates a preferred embodiment retractable spray shield foragricultural use designed in accord with the teachings of the presentinvention in a concealed configuration and in combination with andaffixed to a prior art agricultural spray boom, from a front elevationalview.

FIG. 2 illustrates the preferred embodiment retractable spray shield ofFIG. 1 from an enlarged and partial rear elevational view.

FIG. 3 illustrates the preferred embodiment retractable spray shield ofFIG. 1 in a deployed configuration and in combination with and affixedto the agricultural spray boom, from a front elevational view.

FIG. 4 illustrates the preferred embodiment retractable spray shield inthe concealed configuration of FIG. 1 but without the prior artagricultural spray boom, from a side elevational view.

FIG. 5 illustrates the preferred embodiment retractable spray shield inthe concealed configuration of FIG. 4, from a front elevational view andindicating the movement of the shield during deployment.

FIG. 6 illustrates the preferred embodiment retractable spray shield inthe deployed configuration of FIG. 3 but without the prior artagricultural spray boom, from a side elevational view.

FIG. 7 illustrates the preferred embodiment retractable spray shield inthe deployed configuration of FIG. 3 in combination with and affixed toa prior art agricultural spray boom in operation spraying a crop, from afront elevational view and indicating the movement of the shield duringconcealment.

FIGS. 8-10 illustrate a first alternative embodiment retractable sprayshield for agricultural use designed in accord with the teachings of thepresent invention in a deployed configuration from a side elevationalview, front elevational view with the shield in a first partiallyretracted position, and a front elevational view with the shield in asecond partially retracted position, respectively.

FIGS. 11-12 illustrate a second alternative embodiment retractable sprayshield for agricultural use designed in accord with the teachings of thepresent invention in a deployed configuration from a top plan view andin a substantially retracted configuration from a top plan view,respectively.

FIGS. 13-14 illustrate a third alternative embodiment retractable sprayshield for agricultural use designed in accord with the teachings of thepresent invention in a deployed configuration from a side elevationalview and a top sectioned plan view, respectively.

FIG. 15 illustrates the third alternative embodiment retractable sprayshield for agricultural use of FIGS. 13-14 at an intermediate positionbetween deployed and retracted position from a sectioned top view.

FIG. 16 illustrates the third alternative embodiment retractable sprayshield for agricultural use of FIGS. 13-14 in a retracted position froma sectioned top view.

FIGS. 17-21 sequentially illustrate from a partial and sectioned frontelevational view the third alternative embodiment retractable sprayshield for agricultural use of FIGS. 13-14, retracting the spray shieldfrom a fully deployed position in FIG. 17 to a fully retracted positionin FIG. 21.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Manifested in the preferred embodiment, the present invention provides aretractable spray shield assembly 10 designed for agricultural use incombination with a prior art agricultural spray boom 1. Preferredembodiment retractable spray shield assembly 10 comprises a spray shield20, storage tube 30, deployment and concealment drive 40, and pivotalquick release support and boom arm coupling 50.

As illustrated in FIGS. 1-3, prior art agricultural spray boom 1 may forexemplary purposes include a beam or truss comprising a bottom chord 2,a top chord 4, and a plurality of web members 3 coupling the bottomchord 2 and top chord 4 together. One or more “L”-shaped hangers 5couple to the bottom and top chords 2, 4, and provide a support distalthereto for a liquid carrying pipe 6. Pipe 6 will be coupled at a firstend to a pump as is known in the art, and has a plurality of spraynozzles 7 through which the liquid within pipe 6 may be dispersed over afield. While three spray nozzles 7 are illustrated in FIG. 1, it will beunderstood that any number of nozzles may be provided, and that thesenozzles may be pointed in a plurality of directions.

Spray shield 20 is best illustrated in FIGS. 3-7. A relatively large andgenerally flaccid generally triangular-shaped liquid barrier film 21serves to block the passage of any significant amount of liquid therethrough. While a liquid impervious and hydrophobic material such asplastic sheet manufactured from polyethylene terephthalate,polyethylene, or the like may be preferred for some applications, fabricincorporating any of a variety of materials will also be acceptable forsome applications. One such fabric is known commercially as rip-stopnylon. Regardless of the material, liquid barrier film 21 must besufficiently durable to withstand the force of the spray emanating fromspray nozzles 7, to also withstand repeated collapsing as illustrated inFIG. 4, to withstand repeated fanning as illustrated in FIG. 6, andprovide sufficient chemical resistance to withstand exposure to thevariety of liquids that may be sprayed by prior art agricultural sprayboom 1. Liquid barrier film 21 will also preferably have adequateultra-violet resistance to withstand significant outdoor exposure.

A pair of framing legs 22, 23 are used to alternatively collapse andstretch liquid barrier film 21. These framing legs 22, 23 are pivotallyaffixed to hinge plate 29 through pintles 24, 25. Pintles 24, 25 may beany suitable pivot or hinge that permits framing legs 22, 23 to pivotwith respect to hinge plate 29, and so for exemplary and non-limitingpurpose may comprise shoulder bolts in combination with locking nutspassing through holes or bushing sleeves within framing legs 22, 23. Arelatively larger diameter spring guide post 28 is provided about whichtension spring 27 wraps. Tension spring 27 spans between framing legs22, 23 and is aligned so that any pivoting of framing legs 22, 23 awayfrom the position illustrated in FIG. 6 will stretch spring 27. Thiswill increase the tension in spring 27, meaning spring 27 will resistsuch movement. As a result, under ordinary operating conditions wherespray shield 20 is deployed, such as illustrated in FIGS. 6 and 7,tension spring 27 will hold liquid barrier film 21 in the expandedposition best visible in FIG. 6. However, in the event of anunintentional impact with the earth or other object, framing legs 22, 23are able to pivot, reducing the chance of permanent harm or damage.Tension spring 27 is illustrated as being helically wrapped, but anysuitable tension spring that may span between framing legs 22, 23 whilepassing over spring guide post 28 may be substituted therefor.

Storage tube 30 serves as a receptacle within which spray shield 20 maybe received for storage in an inactive state, and from which sprayshield 20 may be deployed. While illustrated as a square tube, it willbe appreciated that storage tube 30 may take other suitable geometry.Further, storage tube 30 is not required to be fully enclosed, and somay alternatively be open on the top and form a three-sided channel.

Mounted on top of storage tube 30 is deployment and concealment drive40. Drive 40 includes a motor 41, ninety-degree gear box 42, drive shaft43, sprocket 44, chain 45, chain follower 46, idler shaft 47, sprocket48, and pivotal link 49. While a chain drive is illustrated, it will beapparent that other suitable drives may alternatively be used herein,such as but not limited to a belt drive, a hydraulic drive, or a helicalshaft such as an acme screw and a threaded follower.

Motor 41 is most preferably a 12 VDC motor compatible with most farmmachinery, allowing the motor to be powered directly from the sprayerelectrical system without the need for conversion of electricity. Whilenot illustrated, a double pole triple throw or double pole double throwcenter off switch will preferably be provided within the cab of thesprayer that permits the operator to disconnect power to the motor, orto energize the motor in either a forward or reverse direction.

Ninety-degree gear box 42 is optional, but provides compact and durablegear reduction, allowing motor 41 to be a relatively less expensive andmore standard DC motor, and also increasing the output torque whilereducing rotational speed. Nevertheless, motor 41 may directly drive thedrive shaft 43, or may be coupled through a parallel axis gear reducerrather than the ninety-degree gear box 42. Sprocket 44 terminates driveshaft 43, and the teeth of sprocket 44 are configured to engage with anddrive chain 45. Affixed securely to chain 45 is chain follower 46.Consequently, when drive chain 45 turns, chain follower 46 will movelinearly along storage tube 30. While not essential to the presentinvention, chain follower 46 may run in a track at the bottom of oranywhere else within storage tube 30 distal to drive chain 45, if sodesired for better stability. In preferred embodiment retractable sprayshield assembly 10, a pair of guide blocks 31 visible in FIG. 6 maysandwich and thereby prevent chain follower 46 from drifting withinstorage tube 30, and may also provide a linear bearing surface incontact with the wall of storage tube 30.

Adjacent the end of storage tube 30 distal to drive shaft 43 andsprocket 44 is idler shaft 47 that terminates with sprocket 48. As thename implies, idler shaft 47 will terminate in a journal distal tosprocket 48 to permit free rotation about the longitudinal axis.Consequently, idler shaft 47 and sprocket 48 simply maintain directionand tension within chain 45.

The construction of deployment and concealment drive 40 is similar to agarage door opener, including the provision of chain follower 46. Alsolike a garage door opener, some type of travel limit must be provided.The travel limit may be in the form of mechanical stops at each distalend of the travel of chain follower 46 that trigger a detectable forceor torque that is used to shut off power to motor 41. However,electrical switches or position detectors adjacent each distal end oftravel may be provided in alternative embodiments for the same purpose,or other suitable equivalent control may be provided.

While a chain drive is preferred for deployment and concealment drive40, in alternative embodiments other types of drives may beincorporated, including but not limited to a belt drive, a screw drivedefined by a helically threaded shaft such as an acme screw coupled witha female threaded follower, or a linear electric, hydraulic, orpneumatic cylinder drive. The particular form of motive power will bedetermined by a designer. Nevertheless, and as noted herein above, theuse of an electric drive in combination with chain 45 provides a robustdrive that is familiar and readily serviced by most agriculturalmachinery operators, which may be controlled using the existingelectrical system of most sprayers, and which can be easily connectedthrough light weight wires of any needed length.

Pivotal link 49 is coupled adjacent the end of chain follower 46 distalto chain 45. Pivotal link 49 allows the top of hinge plate 29 to climbabove the bottom of storage tube 30 before rotating into longitudinalalignment parallel to the longitudinal axis of storage tube 30. Suchmotion necessarily occurs during retraction of spray shield 20, in thedirection of travel illustrated by arrow 26 b in FIG. 7. When chainfollower 46 moves to the right in that Figure, pivotal link 49 will alsomove to the right. When hinge plate 29 contacts the entrance to storagetube 30, it will tilt to an angle intermediate between vertical andhorizontal, and at that moment the junction between pivotal link 49 andhinge plate 29 will be elevated relative to the bottom of storage tube30.

Pivotal quick release support and boom arm coupling 50 is designed forready installation on a variety of prior art boom arms, whether suchprior art boom arms resemble prior art agricultural spray boom 1illustrated herein or not. Boom arm coupling bracket 51 is designed on afirst end to be either clamped, welded, or otherwise affixed to topchord 4, while the distal end of the bracket is affixed to a pipe 52extending transverse to top chord 4. Pipe 52, visible best in FIG. 2,preferably has a hole drilled through which a retainer such as a cotterpin 53 may pass. Pivotal quick release support and boom arm coupling 50provides a first support. In preferred embodiment retractable sprayshield assembly 10, one or more “L”-shaped hangers 5 provide a secondsupport surface upon which storage tube 30 will rest. In one alternativeembodiment, storage tube 30 may be clamped or otherwise affixed to“L”-shaped hangers 5. In another alternative embodiment, storage tube 30may be coupled through a second pivotal quick release support and boomarm coupling 50.

When desired, the entire assembly of preferred embodiment retractablespray shield assembly 10 other than pivotal quick release support andboom arm coupling 50 may be removed from prior art agricultural sprayboom 1 simply by pulling cotter pin 53 from pipe 52, and then slidingstorage tube 30 off of pipe 52. With the provision of appropriateelectrical connectors, and the disconnection thereof, this is all thatis required to remove preferred embodiment retractable spray shieldassembly 10 from prior art agricultural spray boom 1.

The sequence of deployment and retraction of spray shield 20, and thefunctional operation thereof, is best illustrated in FIGS. 4-7. FIGS. 4and 5 illustrate spray shield 20 in a fully retracted position,generally concealed within storage tube 30. Framing legs 22, 23 willspread from each other at the end adjacent to spring guide post 28,while coming together at the distal end as they are drawn into theinterior of storage tube 30. This allows framing legs 22, 23 to moveinto nearly parallel orientation, appropriate for a storage position,while only nominally interfering with the side walls of storage tube 20.As noted herein above, this concealment is preferred, but in alternativeembodiments for exemplary and non-limiting purpose, when storage tube 30is a three-sided channel as described above, spray shield 20 may simplybe retracted to an inactive position, while remaining visible. As alsonoted herein above, this pivoting of framing legs 22, 23 into nearlyparallel orientation results in an increase of tension within tensionspring 27, meaning tension spring 27 will be tending to oppose thisretracted parallel position.

The arrow 26 a of FIG. 5 illustrates the direction of travel of sprayshield 20 during deployment. This movement is generated by chainfollower 46 being moved by chain 45 in a direction generally away fromdrive shaft 43 and sprocket 44. As spray shield 20 exits storage tube30, it will eventually start to drop distal to the open end of storagetube 30. This drop will continue until hinge plate 29 fully exitsstorage tube 30 and hangs down from adjacent the bottom of storage tube30. This is the deployed position illustrated in FIGS. 6 and 7. In thisposition, tension spring 27 will pull the majority of framing legs 22,23 apart, smoothing out liquid barrier film 21 into the deployedposition of FIGS. 6 and 7. As may be recognized from FIG. 6, in thisposition liquid barrier film 21 is approximately triangular, with thenarrow top point of the triangle immediately adjacent to storage tube30. This narrow top point is therefore also immediately adjacent to topchord 4 and is very near to the most laterally displaced, or outermost,spray nozzle 7. In this location, the spray 8 emitted by a spray nozzle7 has not had distance to fan out therefrom, meaning a narrow point isadequate to capture the bulk of spray 8 that would otherwise compriseoverspray. Liquid barrier film 21 gets wider in the direction of travelof the spray vehicle as the distance increases downward and thereforeaway from spray nozzles 7. Since there will be increased dispersion ofspray 8 with increased distance, this wider base to liquid barrier film21 corresponds therewith.

In the deployed position of FIG. 7, spray shield 20 will not interferewith spray 8 emanating from nozzle 7 that is directed generally downwardtherefrom toward crop plants 9. However, spray emanating in a morehorizontal direction generally parallel to the longitudinal axis ofprior art agricultural spray boom 1, such as spray streams 8 a and 8 b,will contact liquid barrier film 21 or the pair of framing legs 22, 23,meaning spray nozzles 7 will effectively be blocked from overspraying inthat direction.

When a pass along the edge of a field is complete, and the subsequentpasses will be within the field rather than along an edge, then theoperator will control the switch such that motor 41 will be driven tomove chain follower 46 away from idler shaft 47 toward drive shaft 43.This retracts spray shield 20 in the direction of travel illustrated byarrow 26 b in FIG. 7, allowing the spray nozzles 7 to again oversprayadequately to ensure complete coverage within the middle of the field.

As may be apparent then, the operator simply switches the switch fromwithin the spray vehicle cab to deploy preferred embodiment retractablespray shield assembly 10 from the position of FIGS. 4 and 5 to theposition of FIGS. 6 and 7, immediately in advance of prior artagricultural spray boom 1 passing adjacent to the field edge. When thefield edge has been traversed, the operator again simply switches theswitch from within the spray vehicle cab to retract spray shield 20.

A wide variety of materials may be used in the fabrication of preferredembodiment retractable spray shield assembly 10, including spray shield20, storage tube 30, deployment and concealment drive 40, and pivotalquick release support and boom arm coupling 50. These materials mayinclude metals, polymers and resins, elastomers, glass and ceramiccompositions, and laminates, composites, or combinations thereof.However, the materials should be selected to withstand the forces thatwill be encountered during use, the extremes and vagaries oftemperature, weather, and sunlight, and the wear and tear that will beincurred during use.

Various embodiments of apparatus designed in accord with the presentinvention have been illustrated in the various figures. The embodimentsare distinguished by the hundreds digit, and various components withineach embodiment designated by the ones and tens digits. However, many ofthe components are alike or similar between embodiments, so numbering ofthe ones and tens digits have been maintained wherever possible, suchthat identical, like or similar functions may more readily be identifiedbetween the embodiments. If not otherwise expressed, those skilled inthe art will readily recognize the similarities and understand that inmany cases like numbered ones and tens digit components may besubstituted from one embodiment to another in accord with the presentteachings, except where such substitution would otherwise destroyoperation of the embodiment. Consequently, those skilled in the art willreadily determine the function and operation of many of the componentsillustrated herein without unnecessary additional description.

In preferred embodiment retractable spray shield assembly 10, sprayshield 20 is retracted into and deployed from deployment and concealmentdrive 40, which may be configured to fully encompass spray shield 20.This design is particularly resistant to the wind. However, spray shield20 will normally not be used in high wind applications.

In consideration thereof, a first alternative embodiment retractablespray shield assembly 110 is illustrated in FIGS. 8-10 that retracts anddeploys in a different manner. Spray shield 120 incorporates a liquidbarrier film 121, a pair of framing legs 122, 123, pintles 124, 125, atension spring 127, and a spring guide post 128, all which operate in amanner very similar to that of preferred embodiment retractable sprayshield assembly 10. However, instead of a motor and gearbox operating alinear chain drive, in first alternative embodiment retractable sprayshield assembly 110 a motor and ninety degree gear box 141 directlydrive hinge plate 129 in a rotary manner, pivoting hinge plate 129 andspray shield 120 about a drive shaft 143 axis perpendicular to the boomarm and approximately parallel to the earth. Arrow 126 b of FIGS. 9-10illustrates the direction of travel of spray shield 120 duringretraction.

Rather than retracting into a generally enclosed tube, storage tube 130is a three-sided channel that is open on top. As spray shield 120rotates from the deployed position illustrated, framing legs 122, 123will contact a pair of guide blocks 131. Guide blocks 131 willprogressively collapse framing legs 122, 123 together, eventuallyguiding the entirety of spray shield 120 into storage tube 130. While aslightly different embodiment, FIG. 12 illustrates how spray shields120, 220 are located in the retracted position, running longitudinallyparallel to storage tubes 130, 230, respectively.

In first alternative embodiment retractable spray shield assembly 110,guide blocks 131 are simply formed smooth surface extensions of storagetube 130. Guide blocks 131 will preferably introduce only minimalfriction with framing legs 122, 123. Unfortunately, the designobjectives are somewhat contradictory for framing legs 122, 123. As maybe appreciated, these framing legs 122, 123 will most preferably belight weight and still rigid and strong, so that liquid barrier film 121is fully deployed by the spreading of these legs. However, materialsthat are light and strong tend not to be particularly durable.Furthermore, they might not comprise a low or anti-friction composition.As a result, framing legs 122, 123 may be difficult to fully retract,and the repeated sliding in contact with guide blocks 131 may over timeerode the material, leading to premature failure.

To avoid these drawbacks, framing legs 122, 123 may be augmented witheither circumferential sleeves or heavier, low-friction material asidentified by augmented portions 122 a, 123 a. Most preferably, it isthese augmented portions 122 a, 123 a that will engage with guide blocks131 during retraction of spray shield 120.

In alternative embodiments, more elaborate guide blocks may be provided.For exemplary and non-limiting purpose, in one alternative embodimentguide blocks 131 may further comprise roller bearings runninglongitudinally generally parallel with guide blocks 131. In such case,when framing legs 122, 123 come into contact therewith, the rollerbearings will roll, reducing the friction required to be overcome tofully retract spray shield 120. In another alternative embodiment guideblocks 131 may further comprise a low-friction surface layer or coating.Again for exemplary and non-limiting purposes, one such material ispolytetrafluoroethylene, commercially sold under the trademark Teflon™.

In further alternative embodiments, other methods of reducing the forcesrequired to fully retract spray shield 120 are used. In one alternativeembodiment, eccentric cams may be substituted for or mounted onto guideblocks 131, such as in a manner similar to roller bearings. Theseeccentric cams are configured to roll with the movement of spray shield120, and during the roll progressively drive framing legs 122, 123together.

In another alternative embodiment, either eccentric cams or a cable pullmay be provided that release tension spring 127 from spring guide post128. In such case, the cable pull must re-establish tension or theeccentric cams must reset in position during deployment of spray shield120 to ensure that tension spring 127 is functionally engaged withspring guide post 128 prior to full deployment. In a further embodiment,an electrical solenoid may be provided to either shift spring guide post128 to relieve tension in tension spring 127, or to shift tension spring127 away from spring guide post 128 during retraction. In yet anotheralternative embodiment, a gear set and electrical drive motor may beprovided to accomplish similar function.

As illustrated, each of the tension springs 27, 127 are a single,self-centering spring. Nevertheless, there is no requirement of thesame, and in other alternative embodiments two separate and distinctsprings may be substituted therefore. In such case, relieving tensionmay simply be a matter of extending a spacer between the attachmentpoints for the two springs. In other words, the two springs can simplybe spread apart, effectively lengthening them, using any of theaforementioned apparatus to spread the spring attachment points, therebyreduce the tension, and allow for lower force retraction of spray shield120.

FIGS. 11 and 12 illustrate second alternative embodiment retractablespray shield assembly 210 in a retracted position. Retractable sprayshield assembly 210 is, as noted above, similar to first alternativeembodiment retractable spray shield assembly 110. However, retractablespray shield assembly 210 incorporates an electrically driven gear motorlinear actuator 240 of the known type having a motor 241, a gear box242, and a linear drive shaft 243. Linear actuator 240 is preferablysupported by the bottom of storage tube 230, with linear drive shaft 243extending longitudinally parallel to a longitudinal axis of storage tube230. At the end of drive shaft 243 distal to gear box 242, a pivotalcoupling 261 is provided, which may for exemplary and non-limitingpurpose comprise a U-shaped bracket pinned to the end of drive shaft243. Any suitable pivotal coupling may be substituted therefore.

Pivotal coupling 261 is rigidly affixed with U-shaped bar 262. Each ofthe legs of U-shaped bar 262 pass through a cover or guide blocks 263,266 and terminate at a rotatable coupling to shaft 269. Adjacent eachend of shaft 269 are pinion gears 264, 267 that are fixed and notrotatable with respect to shaft 269. Also fixed and not rotatable withrespect to shaft 269 is hinge plate 229.

FIG. 11 illustrates spray shield 220 in a fully deployed configuration,while FIG. 12 illustrates spray shield 220 in a retracted position. Asdrive shaft 243 retracts from the position of FIG. 11 into gear box 242,through pivotal coupling 261 it will also pull U-shaped bar 262 towardgear box 242. This then directly pulls on shaft 269, which will rotatewithin journals such as sleeves or bearings in the ends of the legs ofU-shaped bar 262. Since the teeth of pinion gear 264 are directlyengaged in the teeth of rack 265, and since the teeth of pinion gear 267are directly engaged in the teeth of rack 268, movement of shaft 269toward gear box 242 will cause shaft 269 to rotate. Since hinge plate229 is also affixed to shaft 269, this rotation will also cause sprayshield 220 to rotate. Eventually, spray shield 220 will fully retract tothe position illustrated in FIG. 12. Reversal of linear actuator 240will likewise redeploy spray shield 220 to the position illustrated inFIG. 11.

As may be appreciated, while a number of deployment and concealmentdrives 40, 140, 240 and alternatives thereto have been described, anydeployment and concealment drive capable of rotating spray shield 220through an approximate 270 degree arc of travel will be considered to beincorporated herein. Electrical drives are most preferred, owing to thelow weight and simple installation required for electrical wireextending the length of the boom. For exemplary and non-limitingpurpose, such drives may also include solenoids and other linear motors.Nevertheless, fluid motors including hydraulic, pneumatic, and otherdrives may be used in alternative embodiments.

FIGS. 13 through 21 illustrate a third alternative embodimentretractable spray shield assembly 310. Retractable spray shield assembly310 is, as noted above, similar to the second alternative embodimentretractable spray shield assembly 210. Retractable spray shield assembly310 incorporates linear actuator 340 of known type, which for exemplaryand non-limiting purpose includes an electrically driven motor 341, agear box 342, and linear drive shaft 343. However, in third alternativeembodiment retractable spray shield assembly 310, linear drive shaft 343drives pushing arm 375 of a quadrilateral linkage 370 forward orbackward around pivot 371. Quadrilateral linkage 370 is comprised offour sides made up of pushing arm 375, pivot arm 376, the distancebetween lower pivots 371 and 372 which are held in position by storagetube bottom 331, and the distance between the upper pivots 373 and 374which are affixed to spray shield transport plate 329. Linear actuator340 is preferably pivotally supported by the bottom of storage tube 331,with linear drive shaft 343 extending generally longitudinally parallelto the longitudinal axis of storage tube 330. At the end of drive shaft343 distal to gear box 342, a pivotal coupling 344 is provided, whichmay for exemplary and non-limiting purpose comprise a U-shaped bracketaffixed to the end of drive shaft 343. Any suitable pivotal coupling maybe substituted therefore.

FIGS. 13 and 14 illustrate the retractable spray shield assembly 310 inits deployed position which operates similar to retractable spray shieldassembly 210, where the spray shield 320 which operates in deployedstate is essentially identically to spray shield 220. When spray shield320 is deployed, tension spring 327 wraps around spring guide post 328and pulls on framing legs 322, 323. Framing legs 322, 323 rotate aboutpintles 324, 325 under the force of tension spring 327, biasing framinglegs 322, 323 to hold liquid barrier film 321 in an open position.Pintles 324, 325 and spring guide post 328 are affixed to spray shieldsupport plate 329 and guide spray shield 320 as it moves through thepath that quadrilateral linkage 370 defines.

When spray shield 320 is in the deployed position of FIGS. 13 and 14,spray shield storage tube top 332 remains parallel and touching storagetube bottom 331 by the force of gravity. While not separatelyillustrated, spray shield storage tube top 332 is pivotally affixed tostorage tube bottom 331, and so is free to rotate in a clockwise andcounterclockwise manner as illustrated in FIGS. 17-21, in a clam-shellmanner described further herein below. However, in one alternativeembodiment, a spring is provided to pull spray shield storage tube top332 toward a parallel alignment with storage tube bottom 331. In otheralternative embodiments, other assists may be provided to achieve thisobjective. Again for exemplary and non-limiting purpose, a linear tracksuch as a longitudinally extensive bar or U-channel may be provided thatextends longitudinally just below the top of spray shield storage tubetop 332. In this alternative embodiment, pivot 374 comprises in part apin that protrudes from the sides of spray shield transport plate 329,and this pin is configured to slide within the linear track. In suchembodiment, spray shield storage tube top 332 will follow the movementof pivot 374 and spray shield transport plate 329, irrespective of wind,bumps, and the like that might otherwise lift spray shield storage tubetop 332.

As best visible in FIG. 14 when spray shield 320 is in the deployedposition, linear drive shaft 343 is fully extended by linear actuator340. Linear drive shaft 343 rotates pushing arm 375 to a position nearlyparallel to linear drive shaft 343 and most distal to linear actuator340.

FIG. 15 illustrates retractable spray shield assembly 310 in atransitory position intermediate between the deployed and retractedpositions. In this transitory position, linear actuator 340 is partiallyextended and spray shield 320 is in its expanded state with liquidbarrier film 321 in the open position. FIG. 16 illustrates retractablespray shield assembly 310 in the fully retracted position with linearactuator 340 in its contracted state and liquid barrier film 321 in theclosed position.

The motion of retractable spray shield assembly 310 is best shown by thesequential illustrations of FIGS. 17 through 21. In FIG. 17, retractablespray shield assembly 310 is in its fully deployed position, with sprayshield 320 in its open position. Moving from the fully deployed positionof FIG. 17 to a transitory position of FIG. 18, linear actuator 340retracts and brings spray shield 320 up and more adjacent or closer tolinear actuator 340 by changing the angles within quadrilateral linkage370. Moving from FIG. 18 to FIG. 19, linear actuator 340 retracts more,and spray shield 320 starts to engage with rotating arm guides 379. In amanner similar to guide blocks 131, rotating arm guides 379 guide sprayshield legs 322 and 323 inward to begin closing spray shield 320. Movingfrom FIG. 19 to FIG. 20, quadrilateral linkage 370 continues to rotatespray shield 320 closer to linear actuator 340, in a back and downwardor counterclockwise direction in the Figures, while spray shield 320continues to close. Moving from FIG. 20 to FIG. 21, retractable sprayshield assembly 310 is moved to its fully retracted position, and sprayshield 320 is completely closed. The entire process of closingretractable spray shield assembly 310 is fully reversible, by extendinglinear drive shaft 343 and thereby moving pushing arm 375 and thebalance of quadrilateral linkage 370 from the position of FIG. 21transitioning to the position of FIG. 17.

While in third embodiment retractable spray shield assembly 310, sprayshield 320 is contracted by rotating arm guide 379, spray shield 320 maybe contracted by other mechanisms. In one alternative embodiment, arotating cam is provided that pushes on the shield legs 322 and 323 andpushes the legs closed as rotating arm 376 rotates about pivot 373.Another alternative embodiment uses a geared system to directly drivethe shield legs 322 and 323 off of the rotation of rotating arm 376about pivot 373. In further alternative embodiments, apparatus similarto that described herein above with reference to guide blocks 131 willbe provided to replace or augment rotating arm guides 379.

While the foregoing details what is felt to be the preferred embodimentof the invention, no material limitations to the scope of the claimedinvention are intended. Further, features and design alternatives thatwould be obvious to one of ordinary skill in the art are considered tobe incorporated herein. The scope of the invention is set forth andparticularly described in the claims herein below.

I claim:
 1. In combination, an agricultural spray machine, anagricultural spray boom, and a retractable spray shield for agriculturaluse, the agricultural spray machine having: a drive train; a liquidtank; and a pump receiving a liquid held within said liquid tank; theagricultural spray boom having: a boom arm extending transverse to aforward direction of travel of said agricultural spray machine; and atleast one spray nozzle suspended from said boom arm and in fluidcommunication with said pump; the retractable spray shield foragricultural use having: a hinge plate; a liquid barrier film extendingfrom said hinge plate; a clam-shell storage tube defining a path forsaid hinge plate to reciprocate along, and adapted to receive andconceal said spray shield on an interior when said clam-shell storagetube is closed; a deployment and concealment drive having a motor, adrive shaft, and a quadrilateral linkage including a rotating arm and apushing arm coupled with said drive shaft, said drive shaft rotatingsaid pushing arm relative to said clam-shell storage tube and therebyalso rotating said rotating arm relative to said clam-shell storage tubebetween a first concealed position having said rotating and pushing armsparallel and adjacent to said clam-shell storage tube to a seconddeployed position having said pushing arm parallel and adjacent to saidclam-shell storage tube; and a boom arm coupler adapted to couple saidretractable spray shield to said agricultural spray boom andsimultaneously locate said liquid barrier film in said second deployedposition adjacent to and in a spray pattern of said at least one spraynozzle.
 2. The combination agricultural spray machine, agriculturalspray boom, and retractable spray shield for agricultural use of claim1, wherein said liquid barrier film further comprises a generallytriangular and flaccid liquid barrier film.
 3. The combinationagricultural spray machine, agricultural spray boom, and retractablespray shield for agricultural use of claim 2, wherein said liquidbarrier film further comprises a pair of framing legs, each of said pairof framing legs coupled to an opposed edge of said liquid barrier film.4. The combination agricultural spray machine, agricultural spray boom,and retractable spray shield for agricultural use of claim 3, furthercomprising: a first pintle coupling a first one of said pair of framinglegs to said hinge plate; and a second pintle coupling a second one ofsaid pair of framing legs to said hinge plate.
 5. The combinationagricultural spray machine, agricultural spray boom, and retractablespray shield for agricultural use of claim 4, further comprising: aspring guide post intermediate between said first and second pintles;and a tension spring wrapped about said spring guide post and configuredto operatively stretch said pair of framing legs apart from each otherand thereby expand said spray shield toward a planar, generallytriangular geometry.
 6. The combination agricultural spray machine,agricultural spray boom, and retractable spray shield for agriculturaluse of claim 1, wherein said quadrilateral linkage further comprises abottom of said clam-shell storage tube.
 7. The combination agriculturalspray machine, agricultural spray boom, and retractable spray shield foragricultural use of claim 6, wherein said pushing arm and said rotatingarm are each pivotally affixed at spaced-apart pintles to said bottom ofsaid clam-shell storage tube.
 8. The combination agricultural spraymachine, agricultural spray boom, and retractable spray shield foragricultural use of claim 7, wherein said quadrilateral linkage furthercomprises said hinge plate.
 9. The combination agricultural spraymachine, agricultural spray boom, and retractable spray shield foragricultural use of claim 8, wherein said pushing arm and said rotatingarm are each pivotally affixed distal to said bottom of said clam-shellstorage tube at spaced-apart pintles to said hinge plate.